1. Field of the Invention
The present invention relates to a method and a device for the arithmetical calculation of two-dimensional transforms.
2. Description of Related Art
In many fields of technology there exists the need of executing coding for transmission and recording of numerical signals by means of two-dimensional transforms.
This coding technique ensures the decorrelation of the original signal and executes its energy compacting. Such an operation reduces signal redundancy, allowing the minimization of the quantity of information necessary for coding.
For any type of signal (voice, video, data), the optimum transform in terms of decorrelation capacity is the Karhunern-Loewe transform; unfortunately the computational complexity of the algorithm, and as a consequence the length of calculation time required, makes it difficult to use it within the ambit of industrial applications wherein it is required that the signal transform operation be carried out in real time (coding of images in motion).
In practice different types of sub-optimum unitary transforms are used: discrete Fourier transform, discrete sine transform, discrete cosine transform, Hadamard transform, slant transform.
The choice of a particular type of unitary transform is dictated by the statistical characteristics of the signal to be coded.
The devices available on the market are designed to support only one particular type of unitary transform.